[clang] [Sema] Add code completion for if constexpr and consteval (PR #124315)

[Younan Zhang via cfe-commits]

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@@ -6749,6 +6749,55 @@ void SemaCodeCompletion::CodeCompleteInitializer(Scope *S, Decl *D) {
   CodeCompleteExpression(S, Data);
 }
 
+void SemaCodeCompletion::CodeCompleteIfConst(Scope *S,
+                                             bool AfterExclaim) const {
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zyn0217 wrote:

How about `CodeCompleteAfterKeywordIf`?

https://github.com/llvm/llvm-project/pull/124315